|
Jim,
Looking into warerpump impeller design is way past my desire or ability........I am sure
that with enough time and money a more efficient pump can be had......That being said
I want to get into the air in this lifetime and chose to use the stock pump which has been
proven by Tracy and many others........It has also been documented by several that the
stock pump is on the edge of cavitation between 6500-7000 engine rpm........For that
reason I think it would be prudent to underdrive the pump for those of us using the
RD1C 2.85 redrive........Tracy, Ed and others are already closing in on 7000 rpm in cruise
if they choose........Tracy runs well over 7000 rpm when racing........The reason that the
warerpump pulley in question is 5 inches in diameter is that with the reduced diameter
"Racing Beat" eccentric shaft pulley that most of us use it is impossible use a larger
pulley on the waterpump....... IMHO
--
Kelly Troyer
Dyke Delta/13B/RD1C/EC2
-------------- Original message from Jim Sower <canarder@frontiernet.net>: --------------
> Kelly and all,
> I might have missed this too, but do you know if anyone (like the
> racers) has looked into impeller design of EDWP and come up with
> something that operates better in our envelope? The turbine looking
> design of the EWP suggests that a unit like that /hugely/ underdriven
> would be much more optimal for our purposes. But unless it was really
> popular, would probably be hugely expensive. As for your pulleys, 5"
> doesn't sound like a lot to me. A pump that works in stop-and-go
> traffic with the AC on and engine at idle (< 1000 rpm) seems like it
> would work OK at 7500 rpm with about a 8" pulley, unless you're planning
> on going with a smaller drive pulley to underdrive the alternator too.
>
> I'm currently looking at a 13B with RD1C operating at 7500 rpm cruise
> and capable of 8000 or so if I get in that big a rush. Stock pulleys
> wouldn't do at all for that application I'd think. I need about 210 hp
> for what I aim to do, and extrapolating 160 hp linearly from 6000 rpm
> barely gets me there. Anyway, I need to start keeping better track of
> happenings on this list.
>
> Sorry to be doing all this catching up "on company time" ... Jim S.
>
>
> Kelly Troyer wrote:
>
> > Georges, Ed and all interested,
> >
> > The following excerpt from Bill Jepson adds more info about the stock
> > waterpump and
> > would seem to show the wisdom of reducing pump RPM for those of us
> > using Tracy's
> > RD1C 2.85 redrive.......I will be ordering the 5 " diameter pump
> > pulley today and when
> > received will report on quality, fit, etc as necessary for our
> > needs......
> > --
> > Kelly Troyer
> > Dyke Delta/13B/RD1C/EC2
> > (Copied and pasted from eariler post)
> >
> > Jim, I agree that 12-34 GPM is a big window. One of the items that
> > always drove my skecptisim over the EWP is that in almost every
> > thermodynamic text I've read turbulent flow is cited as helpful to
> > heat transfer. This would be short of cavitation of course. Volume is
> > always the second item, or sometimes interchangeable. I'm sure this is
> > what drives the "other list's" refusal to believe the EWP will work. I
> > AM willing to accept a actual test. Thanks Todd Leon and whoever has
> > tried. Somewhere there is an incorrect assumption being made. I'd like
> > to know where, so I'd be more comfortable, but I am always willing to
> > believe my eyes, and my temperature guage! As a side item, when I
> > spoke with Steve Wienzerl the designer of the newer PowerSport
> > reduction drive, he said they tested the EDWP to max flow. The claimed
> > volume was 55 GPM somewhere between 6500 and 7000 RPM. He was sure
> > this was on the ragged edge of caviitation. He wasn't a EWP believer,
> > in fact he wanted even more flow than they were getting!
> > Bill Jepson
> >
|